Electronic Circuits and Diagram-Electronics Projects and Design

So far I’ve discussed about the micro controller and the compiler software. I’ve yet not written anything about programming.

ATmega32 series micro controllers support 3 types of programming

•   Parallel Programming
•   ISP Programming or serial Programming
•   Programming via JTAG

Here ISP stands for In System Programmer. To burn a micro controller just the burning Hardware is not enough, it requires software also that would download the program present in a computer or memory device into the micro controller.

                Now the software which I am concerned about is named PONY PROGRAMMER 2.06. My circuit is adapted from its website. It uses PC COM PORT to download the program into the micro controller. It have signal amplitude of +5 to +12 volt representing binary ‘1’ and -5 to -12 representing ‘0’.

                The micro controller, ATmega32 is programmed using the pins meant for SPI communication. To enable programming, the microcontroller is taken to the RESET state by pulling its reset pin LOW (Logic 0, or say 0 V), in this state, microcontroller is programmable in either mode (Parallel programming and serial programming). Micro controller always accepts 0 V as logic 0 and +5 V as logic one.

                So as I’ve described before, there is a mismatch between the signal transmitted by PC and signals accepted by the micro controller. Signals are made suitable for micro controller. In the programmer, Zener diodes provide necessary conditioning of the signals. It is so attached that it converts ±12 volt signal to +5-0 volt signal which is suitable for the micro controllers.  A resistance is necessary to limit the current in the nodes of Zener diodes, without the resistors, the voltage can burn the Zener diode, and computer internal circuits may also receive harms.

A high signal (+5V) in the ‘Reset’ pin of micro controller brings it into operational state. A low signal (Ground) drives it into programming mode. As internal pull up resistors are provided at the reset pins, so if nothing is connected to this pin, the micro controller tries to execute the program written within it. Designers may provide a resistance capacitance reset circuit, but it’s not always necessary. Whatever, a push button is used most of the time to provide reset facility. Here in the burner circuit, an open collector output is provided to the reset pin, it is driven by the programmer through the port. This much is enough.

 The necessary data transmission and reception work portion is handles by the pony programmer. Follow the links provided to download pony programmer. The following burner circuit can burn ATmega32 microcontroller, connect the derived signals to the adjacent pins, attach the cable to com port, power up the device i.e. micro controller, and the micro controller is ready to be programmed.

ISP Programmer Circuit Diagram

 

 

So that is how the Circuit is set up, now let me tell you that the micro controller runs upon the internal calibrated RC oscillator in the pictures. So that there is no crystal is attached. Yet the micro controller is programmable. Let us see the software settings. First of all, select the port, to which you have attached the device!  And the programming device from the menu “Set Up>Interface Set Up…”. Select “SI Prog I/O”, this one provides fastest programming speed. And about the ports, it should be com port for this programming cable! Now select the port you have the cable attached to.

 

Now come to the device selection menu. Here ATmega32 belongs to the AVR family. So it is listed under “Devices> AVR micro”. Select ATmega32 as your device. Auto detection will also do.

 

Now after this two vital things check out If your circuit is working or not. Choose “Command>Read All”

Now if you see that it is reading the micro controller without any error message, your programming cable is working and you can program the micro controller with it.

 

You can Burn your hex file with it (Compilers provide hex files to program micro controllers). Just open “File> Open Device File…” now an window will open, now browse for your hex file, load it into the pony programmer, and burn. Pony programmer supports click and drag operation too. That means, if you drop the hex file into the pony programmer, it will automatically catch it.

Components:

DB9 female connector

2 X 1K resistors

2 X 5.1 V Zener diode

1 X 15K resistor

Vero board

BC 547 or any general purpose NPN transistor

Male Relimate connector (6PIN & 2PIN)

Links for Reference:

ATmega32 datasheet

Pony Programmer download page

Pony programmer 2.06 download

Note: 1. Make sure that you have a COM PORT in your computer hardware and your operating system recognizes it. Check it from “Control Panel > Administrative Tools > Computer Management”. In the cascaded list pane, find the following

“Computer Management > System Tools > Device Manager > Ports (com & LPT)”. If COM ports are present under this list, this circuit will work fine. Else, look for a USB based burner.

Note 2. This burner will work fine for ATmega16 too.  For ATmega8, you need to connect the signals to the respected pins.

Note 3 .You can omit the male 2-PIN Relimate connector

 Bibliography

Lancos.com and Atmel

Mr. Gaurav Chaudhuri’s Blog